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ANALYSE THE EFFECT OF DELAYED RECOVERY ON DENGUE

EPIDEMICS THROUGH THE SEIR MODEL

RAJA NORAFIFAH SYAZLIYANA BINTI RAJA AZUAL (K242/59)

SUPERVISOR: PN. RAHAIDAH BINTI MUHAMMAD

ABSTRACT

Dengue fever is a serious disease spread by mosquitoes, especially in hot countries. Peo ple who are infected will feel sick for a few days or weeks. This gives

mosquitoes more opportunity to bite them and spread the virus to others. For this project, I investigated the spread of dengue using a mathematical model know as

the SEIR model. I focused on the effects of delayed recovery, which happens when people take a long time to recover from dengue. I changed the model’s recovery

rate and tested the effects of slow, normal, and fast recoveries on the number of sick patients using the MAPLE software. The re sults showed that when people

recovered slowly, the outbreaks became larger and lasted longer. But if people recovered quickly, fewer people got sick and the outbreak ended sooner. According

to the study, faster recovery might avoid dengue from spreading far and wide. Controlling dengue outbreaks needs immediate action and the offer of early

treatment. The study also helps medical professionals in understanding the importance of recovery time in developing strategies that avoid dengue from spreading.

PROBLEM STATEMENT OBJECTIVES

Dengue is a serious health issue in many tropical countries due to rising cases and frequent outbreaks. One 1) To formulate the SEIR model of Dengue Epidemics infection.

important factor is how fast infected people recover. If recovery is delayed, the risk of spreading the disease 2) To investigate the effects of delayed recovery on the disease-

increases, especially in areas with many mosquitoes. free and en pidemic equilibrium points of the SEIR model.

3) To analyse the impact of delayed recovery on the spread and
Most existing models do not fully study the effect of delayed recovery. This project uses the SEIR model to fill that

gap by including delayed recovery in the analysis. By studying how recovery time affects infection rates, outbreak dynamics of dengue epidemics

size, and stability, the study helps improve strategies to control dengue more effectively.

METHOD

Stability Analysis IMPLEMENTATION
List of Parameter

Equilibrium Point

a) Disease-Free Equilibrium b) Stability Analysis of Endemic Equilibrium

SEIR Model Diagram and System of Ordinary

Differential Equation

b) Endemic Equilibrium

a) Local Stability of Disease-Free Equilibrium

Stability Analysis

a) Stability Analysis of Disease-Free Equilibrium

Basic Reproduction Number

Equilibrium Point

b) Local Stability of Endemic Equilibrium

R0 is more than 1 which means that, the points given by the disease-

free equilibrium (DEEP) will be unstable

Since not all the roots of equation are negative, the system is unstable.

CONCLUSION

The SEIR model shows that recovery time has a strong impact on dengue

outbreaks. Slow recovery leads to a higher number of infections and longer
RESULTS & DISCUSSION

epidemics. In contrast, fast recovery reduces the spread and helps the outbreak

end sooner. This proves that early diagnosis and quick treatment are crucial in

stopping dengue. The mathematical model also gives useful insights to improve

real-world health strategies and outbreak response.

RECOMMENDATION

Encourage early treatment to shorten recovery time and reduce

transmission.

Improve public awareness on dengue symptoms and the importance of

getting help quickly.

Provide quick access to medical care, especially during peak dengue

seasons.

Strengthen mosquito control efforts such as fogging and clean water

storage.

Enhance the SEIR model in future research by including weather effects,

reinfection, vaccination, and mosquito population changes.